The invention relates to a hydraulic hammer comprising: a frame, which is an elongated piece and comprises an upper end and a lower end; a percussion device having an elongated percussion piston that is reciprocatingly movable into a stroke direction and a return direction by means of hydraulic pressure. The invention further relates to a tool bushing for supporting a tool to a hydraulic hammer.
A hydraulic hammer is used as an additional device in an excavating machine or other basic machine for example for purposes of breaking rock, concrete, or some other relatively hard material. The hydraulic power needed by the hydraulic hammer can be led to the hammer's percussion device from a hydraulic circuit of the basic machine. The percussion device delivers strokes to a tool attached to the hydraulic hammer and the tool transmits the strokes to the material to be broken. The percussion device usually includes a percussion piston, which makes a reciprocating movement by the impact of hydraulic pressure and delivers strokes to a stroke surface on the upper end of the tool. At the same time when delivering strokes with the percussion piston, the tool is pressed against the material to be broken, whereby the tool penetrates into the material by the impact of the strokes and the pressing, and causes the material to break. The hydraulic part of the percussion piston is sealed to prevent leakage of hydraulic fluid. However, a problem with hydraulic hammers is the arrangement of seals at the lower end of the percussion piston, i.e. at its tool side end. In current solutions the mounting of the seals and the changing thereof in connection with maintenance is laborious.